Literature

Articles & Papers

White Papers and Presentations

Attracting Women to Hydro: The Push for Innovation and Gender Equality in an Aging Industry

In a rapidly aging industry that is both critical to the nation’s infrastructure and in danger of losing vast portions of its specialized knowledge base as experienced veterans retire, it has become crucial to develop larger, more vibrant, and more competitive candidate pools. A targeted focus on workforce development for women in hydro is a critical step in addressing that need. This article will address not only how to entice younger professionals to take a role in our clean energy future, but specifically how to attract women to this career path.

Despite its status at the dominant, most reliable renewable energy source in the United States, hydropower receives much less recognition than either solar or wind power. By engaging, educating, and considering those who may not consider hydro, we can promote hydropower as the number one renewable energy solution of the future.

Life After the OEM: Case Studies from Customers Who Lost OEM Support Following a Merger or Acquisition

For an Asset Manager, one of the worst days of your life can be the day you learn that your Equipment OEM has just merged with another company, or been acquired by another company. “How will this change the support I receive?” “Who will I be able to call when I have a problem?” “How many of the people I used to know and work with will still be around in three months? Or three weeks?!” “What will we do if we can’t get support for our existing systems?”

This presentation studies several organizations who have lived through such disruptions and emerged on the other side; what their experiences were, good and bad; what alternative strategies they developed to support their existing equipment; and what recommendations they would offer others who are experiencing similar disruptions.

In order to advance the hydropower industry, we must increase the acceptance of hydropower as a renewable energy. The industry needs to take an all-inclusive approach to promoting hydropower, especially considering those who don’t consider hydro.

From the earliest mechanical governors to today’s microprocessor-controlled control systems, much has changed in the way hydroelectric powerplants are controlled, yet much remains the same. The primary functions of the governor still remain: sensitivity to the smallest frequency excursions when islanded, and a predictable, sustained Droop response when grid-connected. The question is how (and whether) to maintain the performance of legacy governors, some of which date back to the early 20th century.

This paper provides a case study of a European utility who, when faced with the prospect of an expensive governor replacement programme, came up with an innovative solution to extend the useful life of their legacy governors.

Minimizing the environmental impact of hydroelectric power generating facility is a key component in many organizations’ environmental policy. One of the largest concerns in a hydroelectric plant is the risk for potential water contamination through leaking oil, especially in the turbine pit. This paper will consider why traditional oil is preferred by operators and manufacturers rather than modern environmentally-friendly biodegradable oil. This paper will also evaluate the importance of oil commonality within an organization. Several experts in governor manufacturing and maintenance were consulted for their input as to the techniques that should be used to ensure the maximum performance and longevity of a governor system as well as mitigate environmental contamination.

A HydroVision International 2013 Technical Paper of the Year | View Award

Dinorwig Power Station, located in North Wales, UK is one of the largest Pumped Storage facilities in Europe and has the capacity to generate electricity with six (6) 300MW pump generator units. These units make a significant contribution to ensuring the day-to-day stability of the UK, which relies on the Dinorwig Powerhouse to deliver rapid, consistent response. Upgrading the digital governor controls on Unit #1 resulted in reliable, accurate and faster response to a range of frequency excursions. This paper provides an insight to this achievement, which has re-enforced Dinorwig as one of the leading Pumped Storage plants in the World.

Authors: Greg Yohe with Toni Jones of First Hydro Company
Presented at HydroVision International 2013 – Denver, CO

This presentation provides an overview of how generators on large electrical grids respond to frequency disturbances and describes why hydro is critical to a well-functioning grid. The concepts of primary, secondary and tertiary control are discussed, as are the varying – and in some cases extremely limited – contributions provided by other types of generation including: fossil, nuclear, reciprocating engines, wind, and solar.

Considering the current trend of increasing penetration of wind energy into electrical grids, this presentation will debunk current fallacies about the degree of grid support that is available from modern wind turbines and discuss the likelihood of wind farms voluntarily agreeing to generation curtailments to support real-time grid needs. Finally, this will present several concrete ways in which owners of hydro units can expand and strengthen their ability to provide – and get paid for – first-line-of-defense responsiveness to grid frequency disturbances.

Mighty River Power (MRP) is one of the leading utilities on the North Island of New Zealand. They have been maintaining a collection of diverse governor and Hydraulic Power Units (HPUs) that are all original and date from the 1940s. Due to attrition and downsizing within the company, the number of technicians who know how to tune, adjust, overhaul and otherwise support these diverse mechanical and early analogue governor control systems has dwindled to the point where the utility was concerned a governor component failure could idle a unit for up to nine months.

In conjunction with their exciter/voltage regulator and protective relay upgrade programs already underway, in 2011 MRP initiated and funded a project to modernize their fleet of governor systems to be compatible with the new Unit / Plant Control and SCADA systems. This presentation describes how MRP developed and implemented a strategy to convert and standardize their governor and hydraulic systems.

The end goal is to modernize and standardize all 20 hydro units in their system, so that a small team of trained technicians can support these systems for decades to come, without having to “re-learn” the software, electrical and hydraulic interface at each plant. Likewise, their remote Dispatch Center will have Governor Control screens that are uniform and consistent.

Mitigating the Costs of Equipment Failures in Modern Hydroelectric Control Systems

During the design phase of modernized hydroelectric control systems, there is often great concern and confusion surrounding the topic of equipment redundancy. Redundancy promises to improve system reliability, but comes with the upfront costs of additional equipment, significantly increased engineering costs, and the long term costs of increased system complexity. Unit availability at hydroelectric installations is critical to grid reliability, water conveyance and utility revenues; therefore unexpected unavailability commonly comes with hefty penalties in addition to lost generation revenues. Because of this the benefits of redundancy are often viewed as outweighing the costs.

While this is generally true for the largest of installations, it is not always the case for smaller plants. This presentation will look the continuum of methods which can be employed to improve control system reliability. Varying levels of redundancy will be examined, from simple component redundancy to full-blown triple modular redundant approaches.

Additionally, alternate means of mitigating the costs of equipment failures will be explored. These will include preventative maintenance plans, comprehensive personnel training and spare parts stocking strategies. Each tactic will be evaluated for its short and long term costs and its effectiveness in minimizing three metrics: Mean Time Between Failures (MTBF), Mean Time to Repair (MTTR) and Mean Time Between Forced Outage (MTBFO). To provide application examples, several recent hydro governor modernization projects will be studied. Details of the approach taken, comments from the plant owner on why their approach was chosen and lessons learned will all be included.

Utilization of turbine-generator system modeling can provide distinct advantages when considering capital improvement projects in hydropower facilities. Such modeling both facilitates the decision-making process for turbine control modernization projects as well as the design and validation of specific turbine control systems.

Hydropower generation has been shown to provide the most substantial component of Primary Frequency Control of any generation type in the Western Electricity Coordinating Council (WECC). Primary Frequency Control is an important component of grid reliability and as such is regulated by the North American Electric Reliability Corporation (NERC). This paper explores the untapped potential for increasing hydro’s role in improving grid reliability via Primary Frequency Control by adding or maintaining governor systems at smaller plants.

Governor systems are required to always meet or exceed the performance and reliability requirements of IEEE 125 “Recommended Practice for Preparation of Equipment Specifications for Speed-Governing of Hydraulic Turbines Intended to Drive Electric Generators”, as well as meeting expanding NERC Reliability Standards. Very careful consideration must be given when designing replacement plant or unit controllers. Using real-world examples, this paper will describe the potential for current and future difficulties with this type of integrated control scheme, discuss situations where the integrated system strategy may be used successfully, and identify the critical issues to consider when developing a controls retrofit strategy.

Secondary frequency regulation service, also known as Automatic Generation Control (AGC), is one of the tools regional transmission organizations (RTOs) and independent system operators (ISOs) use to balance supply and demand to maintain reliable grid operations. On October 20, 2011, the Federal Energy Regulatory Commission (FERC) issued Final Rule #755 regarding frequency regulation compensation in the organized wholesale markets. This final rule affects the compensation that energy providers receive for their services.

Multiple needle impulse turbines are among the most efficient designs of hydroelectric turbines, however are often restricted from reaching their full operating potential due to control limitations in their legacy governor systems. Mechanical, analog and early digital governors lack the ability to separate control of the deflector and the individual needles, which results in numerable operating obstacles: primarily poor needle control and the inability to realize the maximum efficiency of the turbine. Today, modern digital controllers and hydraulic controls allow for precise, independent positioning of the deflector and each needle, and therefore needle sequencing. With these key features, all of the aforementioned shortcomings can now be overcome.

The Impact of Hydroelectric Power on Grid Frequency Stability for the WECC Region

With the increased use of variable forms of generation such as wind and solar, there is increased concern not only about load matching, but grid stability itself. Hydropower plants often are proposed to back-up variable sources due to the ability of hydropower plants to store their fuel/energy. In addition to compensating for the hourly and daily variations in output from wind farms and solar plants, hydropower plants can also make significant contributions to grid stability through the capabilities of their governing systems.

The US Bureau of Reclamation (USBR) Grand Coulee Third Powerhouse has the largest hydro units in North America at approximately 750MW each. Together they total approximately 4.5GW, making it one of the largest power plants in the world. Facing increasing difficulty obtaining spare parts for the 30+ year old analog governors used on these units, USBR decided to contract for turnkey digital governor conversions on all six units in this powerhouse over a period of three years. The governor project is scheduled in tandem with the installation of new voltage regulator/excitation systems.

Large Scale Governor System Retrofits: U.S. Army Corps of Engineers, North Pacific Region

Throughout the Pacific Northwest the U.S. Army Corps of Engineers owns and operates 21 hydroelectric powerhouses. The mechanical and analog governor systems that control the turbines in these facilities include a wide variety of manufacturers: Woodward, Pelton, Voest-Alpine, and Allis-Chalmers. The turbines are predominately Kaplan type, but also include a number of Francis units. In an effort to enhance operational efficiencies the U.S. Army Corps of Engineers has begun the process of converting all of the 146 governor systems
to a standardized digital control platform with a common electro-hydraulic interface.

As part of a major plant upgrade, Pacific Gas & Electric (PG&E) is replacing the analog governors on three 404MW units at the Helms Pumped Storage plant. Because this is a critical plant, the new governor system features fully redundant PLC controls and feedback sensors, as well as redundant hydraulic control manifolds. This paper provides an overview of redundancy concepts and a description of the redundancy and fail-safe features included in the Helms governor design.

Low-pressure hydraulic governor systems – as well as other hydraulic systems in hydropower plants – require a significant quantity of oil: thousands of gallons, in some cases…The idea of replacing hundreds or even thousands of gallons of petroleum-based oil with biodegradable oil, with no loss in plant performance or durability, had merit to our engineers.

For 14 years, the U.S. Army Corps of Engineers (USACE) experienced intermittent governor stability problems with units at its 2,160-MW John Day Dam on the Columbia River. Symptoms included hunting and difficulty synchronizing. It was discovered that the output voltage of the permanent magnet generator (PMG) was low, suggesting that the PMG needed to be remagnetized. American Governor Company (AGC) designed a special apparatus to remagnetize the PMG. Following remagnetization, the governors operated normally.

Authors: Roger Clarke-Johnson with David Shank, P.E. and Jack Dean of U.S. Army Corps of Engineers
Published in Hydro Review, November 2006

Perhaps the most common hydro governor in the world today, the Woodward Gateshaft governor is now as it was then: “a simple, strong and durable” device capable of “accuracy and smoothness in the control of load changes.” Designed to last a hundred years, thousands of Gateshaft governors remain in use today, still functioning and largely unchanged after nearly a century of service.

Author: Gerald Runyan
Published online at Energy Central, October 2002

In today’s hydro industry, where the availability of qualified candidates, competitive factors, and an aging workforce of skilled hydro experts have all combined to create a maelstrom of demand for employee development and training, American Governor Company (AGC) is at the vanguard of affecting real change in the industry’s ability to meet these needs. As the world leader in providing control system service and support in the hydropower industry, AGC has also become a leading provider of advanced, transportable simulators utilized to address the inherent challenges of training powerplant personnel in a high-quality and effective manner.

A number of governing methodologies are available including Proportional-Integral-Derivative (PID), lead-lag, double-derivative, and other variants introduced by modern control theory. Unfortunately no variant is best suited for all conditions. For the Grand Coulee Dam’s Third Powerhouse governor upgrade, a fourth order lead-lag governor was used. For this particular application, a fourth order lead-lag controller provides superior feedback control over a PID type controller. This poster demonstrates the robustness comparison and is supplemented by data recorded from the actual governor upgraded at Grand Coulee Dam’s Third Powerhouse. This robustness and sensitivity analysis can serve as a model for other power plants.